IS 14.] On the Porcelain Earth of Cormvall. 183 



bottom, through which the water let off is conveyed to a drain 

 underground. The pits also, when it is intended to preserve their 

 contents, are furnished with a similar apparatus. 



The water running from the heaps of clay is first received in a 

 pit^ which it is allowed to till : the coarsest of the suspended par- 

 ticles subside, and the lighter and finer are conducted from the 

 surface in the overflowing water by channels, or wooden spouts, to 

 other contiguous pits of nearly the same dimensions : in these it 

 deposites still further the coarser part of its contents, and overflowing 

 carries otf only the finest particles of clay. 



In the bottom of the first pit there is an opening, with a trap or 

 valve, through which the coarse parts that have accumulated are 

 allowed to run off" at the end of each day's work. The deposit of 

 the second pits is collected from time to time, by gradually Jetting 

 oft" the water from above it, for the purpose of being dried separately, 

 and Sent to the potteries. It bears the name of " mica," and 

 appears, in fact, to consist principally of that mineral. There is, 

 however, in this part of the process some variation, depending on the 

 object and judgment of the manager. In some of the works the 

 " mica " is not preserved ; and in some there are three pits, through 

 which the water passes before it arrives at the ponds, the deposit of 

 one or more of them being preserved or rejected according to cir- 

 cumstances. 



The water which has come from the pits being received in the 

 ponds is allowed to extend itself, and gradually to deposit it< con- 

 tents. As the mass of clay increases at the bottom, the openings in 

 the boards at the sides are successively stopped with plugs, which 

 prevent the escape of any but the clearest water; and thus tlie 

 accumulation continues until the pond is full. 



The contents of the ponds, when they are filled, are transferred 

 from them in hand-barrows to what are called '^ pans," which are 

 shallow excavations adjacent to the ponds, and like them lined with 

 granite. Tlievare generally about forty feet in length by twelve in 

 width, and about fourteen inchc'* deep ; their extent and liumber 

 being proportioned to the dimensions of the ponds. The clay, now 

 in the state of a thick mud, is distributed uniformly over the bottom 

 of the pans to the depth of from ten to fourteen inches, with a 

 wooden instrument like that in common use for scraping roads ; and 

 it remains to dry for a length of time, which varies from four months 

 to eight, according to the season and the weather.* VVh.at has 

 accumulated during the summer months, being put into the pans in 

 September, is generally found to be firm and nearly dry about the 

 following April or M'ly'. The depth of the mass in this stale varies 

 with the height to which the pans have been filled, ar>d the thick- 

 ness of the clay when introduced. It is now cut with large knives 



• It it not imprubabic thnt this lone exposure to the .nir in a inoi>l state may 

 rrii<l«-r the clay more li( Tor tlu' (jurpose^ of the inaiuiCactiiror, h\ {iruinoliii; Uic 

 rfri uuiputiliun uf the fclijjai 



